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Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 1.

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Presentation on theme: "Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 1."— Presentation transcript:

1 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 1

2 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 2 Contents Is nervous system (NS) necessary for behaviour? What was first? Sensory neurone or motor neurone? NS phylogenesis with regard to motor control Basic units that control movement in mammals Logic of motor control. Fusimotor system. Direct control by motor cortex Cerebellum – a mystery? Basal ganglia = plans of actions

3 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 3 Is nervous system necessary for behaviour?

4 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 4 Behaviour was first, neurones were second Protists have no neurones, yet they display: - Active predation - Phototaxis - Gravitaxis - Chemotaxis - Mechanoresponsiveness Cilia-driven locomotion Single-cell organisms perform both sensory and motor function

5 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 5 What was first? Sensory neurones or motor neurones? (Sensory receptor)-like neurones controlling non-neural motility of primitive ciliated organisms => Sensory neurones were first Sensory-motor unit Sensory-motor unit

6 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 6 Motor neurones have evolved along with muscle cells. Muscle cells are controlled by motor neurones

7 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 7 Cnidaria

8 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 8 Molluscs – ganglia Pedal ganglia

9 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 9 FMH Output Vertebrate brain

10 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 10 Vertebrate brain C. J. Herrick ( ) Brain of the tiger salamander

11 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 11 Vertebrate brain Brain of the tiger salamander

12 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 12 Levels of mammalian motor control Motor cortex Basal ganglia Brain stem Cerebellum Spinal cord Motor unit

13 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page pairs of spinal nerves Sensory & motor nerves Spinal cord

14 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 14 Spinal cord α motor neurone γ motor neurone

15 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 15 Muscle fibre Muscle Muscle fasciculus Muscle fibre Myofibril α motor neurone

16 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 16 Motor unit = α motor neurone + extrafusal muscle fibres

17 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 17 Extrafusal fibres Intrafusal fibres Alfa motoneurone Gamma motoneurone Muscle spindle Muscle structure

18 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 18 Proprioception Muscle spindle - Sensory ending - Motor ending ( γ ) Golgi tendon organ

19 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 19 Golgi tendon organ

20 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 20 Muscle spindle

21 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 21 Muscle spindle - Stretch reflex vs. Voluntary contraction α and γ co-activation Spindle lengthened

22 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 22 Spinal reflexes Afferent inhibitionStretch reflex

23 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 23 Spinal reflexes Recurrent inhibitionTendon reflex

24 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 24 Spinal reflexes Flexor withdrawal reflex

25 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 25 Levels of mammalian motor control Motor cortex Basal ganglia Brain stem Cerebellum Spinal cord Motor unit

26 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 26 Motor cortex Motor homunclus

27 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 27 Motor cortex Primary - agranular Premotor - dysgranular Supplementary - dysgranular

28 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 28 Motor cortex connections; Tracts PM MI MII vl talamus cerebellum spinal cord av talamus pallidum n. ruber medul. rf pont. rf SISI SISI

29 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 29 Pyramidal tract

30 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 30 Red nucleus – a relict Corticorubral tract Rubrospinal tract Nucleus ruber is under the control of the cerebellum

31 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 31 Brain stem control of posture Stimulates antigravity muscles. Afferent connections: - All vestibular nuclei - Cerebellum Stimulates antigravity muscles. Afferent connections: - All vestibular nuclei - Cerebellum Relaxes antigravity muscles. Afferent collaterals from: - Pyramidal tract - Rubrospinal tract - Other motor pathways Relaxes antigravity muscles. Afferent collaterals from: - Pyramidal tract - Rubrospinal tract - Other motor pathways Pontine reticular nuclei Medullary reticular nuclei Vestibular nuclei

32 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 32 How to explain voluntary movements?

33 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 33 Motor cortex Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output Motor as well as sensory cortical areas represent (code, remember) real ‘objects’. Similar to primary sensory cortices that code sensory primitives, primary motor cortex codes motor ‘primitives’ – muscles. The premotor and suplementary motor cortices code for more abstract motor ‘objects’, e.g. movements. Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output Motor as well as sensory cortical areas represent (code, remember) real ‘objects’. Similar to primary sensory cortices that code sensory primitives, primary motor cortex codes motor ‘primitives’ – muscles. The premotor and suplementary motor cortices code for more abstract motor ‘objects’, e.g. movements.

34 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 34 Motor cortex Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output Sensory cortical areas send their output to the associative areas which represent reality in a complex and abstract way. As the overall goal is to control behaviour, these cortices send their output to areas that store plans of actions, patterns of behaviour. Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output Sensory cortical areas send their output to the associative areas which represent reality in a complex and abstract way. As the overall goal is to control behaviour, these cortices send their output to areas that store plans of actions, patterns of behaviour.

35 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 35 Motor cortex Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output Primary sensory cortical areas are a representational substrate located closer to the input side of information flow. Motor cortex is a representational substrate closer to the output side, i.e., closer to structures that control behaviour. Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output Primary sensory cortical areas are a representational substrate located closer to the input side of information flow. Motor cortex is a representational substrate closer to the output side, i.e., closer to structures that control behaviour.

36 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 36 Motor cortex Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output The CNS structures, activated in this order: Sensory neurone, Thalamus, Primary sensory cortex, Higher-order sensory cortices, Associative cortical areas, Prefrontal cortex, Striatum, Pallidum, Thalamus, Motor cortex, and Motor neurone, can be considered an improved reflex arc......(conditioned) Organisation of CNS Cerebral cortex = neural substrate for mnemonic representation of the external and inner world Sensory signals lose meaning unless they can control behaviour Each structure has an output The CNS structures, activated in this order: Sensory neurone, Thalamus, Primary sensory cortex, Higher-order sensory cortices, Associative cortical areas, Prefrontal cortex, Striatum, Pallidum, Thalamus, Motor cortex, and Motor neurone, can be considered an improved reflex arc......(conditioned)

37 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 37 Phylogenetic principle of inteligence Thalamo-cortico-striatal system Mesencephalon Medulla

38 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 38 From stimulus to voluntary action Sensory organ – stimulus detection, registration of reality Primary sensory cortex – sensory primitives Thalamus - ? Higher-order sensory cortices – abstract representations Associative cortical areas – abstract non-sensory representations Prefrontal cortex – interpreter of information Striatum – database of efferent programs (action templates) Pallidum – ‘point of no return’, release vs. termination of action Thalamus - ? Motor cortex – representation of motor units

39 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 39 Basal ganglia Striatum = caudate nucl. + putamen Globus pallidus Nucleus accumbens Nucleus subthalamicus Substantia nigra

40 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 40 Basal ganglia

41 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 41 Basal ganglia

42 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 42 Motor cortex connections; Tracts PM MI MII vl talamus cerebellum spinal cord av talamus pallidum n. ruber medul. rf pont. rf SISI SISI

43 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 43 Cerebellum Motor control (both voluntary and automatic) can proceed without the cerebellum.

44 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 44 Cerebellum

45 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 45

46 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 46

47 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 47

48 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 48

49 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 49 The cerebellum has probably evolved as a means of maintaining our body in optimal orientation relative to gravity under all circumstances through motor control. In support of this hypothesis is the fact that the oldest part of the cerebellum is the flocculus which responds to vestibular signals by maintaining body balance and corresponding eye movements. The cerebellum has probably evolved as a means of maintaining our body in optimal orientation relative to gravity under all circumstances through motor control. In support of this hypothesis is the fact that the oldest part of the cerebellum is the flocculus which responds to vestibular signals by maintaining body balance and corresponding eye movements.

50 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 50 Cerebellum Anterior lobe Posterior lobe Flocculonodular lobe Vestibulocerebellum (flocculonodular l.) Cerebrocerebellum (lateral part) Spinocerebellum (medial part) Anatomical division ‘Functional’ division

51 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 51 Cerebellum – fine neural structure Purkynje cell Parallel fibre Granule cell (3/4 of all) Mossy fibre Deep cerebellar nucleus Inferior olive (in the medulla) Climbing fibre

52 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 52 Cerebellum – afferent connections Cortico-ponto-cerebellar pathway Olivocerebellar tract (climbing fibres from the inferior olive) Vestibulocerebellar pathway Spinocerebellar pathway

53 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 53 Cerebellum – efferent connections Thalamus Basal ganglia Nucleus ruber Nucleus reticularis pontis

54 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 54 Cerebellar lesion Cerebellar activation during speaking Play from web

55 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 55 Cerebellum The cerebellum is probably one of two elementary feedback mechanisms of the motor system that adjust movements. The first is the fusimotor system (gamma motoneurone) which functions on the basis of spinal feedback. The second is the cerebellum that works like software. It adjusts signals – that are sent to muscles by the motor cortex – in a way that the result exactly corresponds to the wanted movement. The cerebellum is probably one of two elementary feedback mechanisms of the motor system that adjust movements. The first is the fusimotor system (gamma motoneurone) which functions on the basis of spinal feedback. The second is the cerebellum that works like software. It adjusts signals – that are sent to muscles by the motor cortex – in a way that the result exactly corresponds to the wanted movement.

56 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 56 Play from web

57 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 57 The end

58 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 2

59 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 2 coactivation of the alpha and gamma motor neurons coactivation keeps the muscle spindle reflex from opposing the muscle contraction Activation of muscle spindles on opposite sides of a joint elicits reflexes on both sides and fixates it. The purpose of patelar reflex test is to determine how much background excitation, or “tone,” the brain is sending to the spinal cord Golgi tendon organ: reflex provides a negative feedback mechanism that prevents the development of too much tension on the muscle

60 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 2 Ovládání svalu – fusimotorický systém

61 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 2 Ovládání svalu – fusimotorický systém Svalové vřeténko - signalizuje natažení (délku) intrafusálního vlákna. Golgiho šlachové tělísko - signalizuje napětí svalu.

62 Department of Physiology, 2 nd Faculty of Medicine, Charles University Copyright © 2011 Luděk Nerad Motor control Neurophysiology page 2 Ovládání svalu – fusimotorický systém Alfa motoneuron - aktivuje kontrakci svalu (extrafusálních vláken) Gamma motoneuron - aktivuje kontrakci intrafusálních vláken


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